The ability of HIV-1 proteins, particularly the transactivating protein, tat, to regulate cellular functions helps explain the dysfunction of the nervous system in brain tissue where there is little evidence of active virus multiplication. We found that HIV-1 up regulates the synthesis and release of the beta-chemokine MCP-1 which is also found in elevated levels in the CSF of AIDS patients with dementia. There was also elevated levels of mRNA to MCP-1 in brain tissue from demented patients. Investigations of CSF samples from HIV-1 infected non-demented patients as well as non neurologically impaired patients did not show increases in MCP-1 in the CSF. This observation has now been confirmed by several other laboratories and may serve as a surrogate marker for AIDS assoicated dementia. Also there was no evidence for other chemokines in the CSF of demented patients suggesting that MCP-1 plays an unique and important role in pathogenesis. We have also shown that human astrocytes are responsible for MCP-1 release in a model of the blood:brain: barrier with endothelial cells. Also the MCP-1 released chemoattracts monocytes across the barrier and upregulates the beta-chemokine HIV-1 co- receptor, CCR5, on migrating monocytes. The molecular regulation of MCP-1 in astrocytes may be controlled by transcription factors which also regulate JCV infeciton, namely NF-1. The promoter sequences of the human MCP-1 promoter shows inducible NF-1/AP-1 sites which are sensitive to the HIV-1 protein tat. We are now testing a series of wild type and deletion mutant MCP-1 promter expression vectors to identify the critical DNA binding regions which are responsive to tat up- regulation in human astrocytes. It appears that sequences from -300 to -420 from participate in MCP-1 mRNA synthesis upon tat stimulation. We had previoulsy established a cell culture model of HIV-1 infection in human astrocytes closely resembling a viral latency. Upon treatment of HIV-1 latenly infected cells with proinflammatory cytokines like TNF-a, the viral genome is activated and new progeny virions are released. We have now shown that IL-1 beta and the tat also activate new virus synthesis. This infectious process however is not cytopathic to the cells which suggests that the astrocyte may serve as a reservoir for HIV-1 in the brain. With the emphasis on the development of an AIDS vaccine, understading the mechanims of HIV-1 infection in human brain is critical to the use of a vaccine. If reactivation of a latent infection from a sequestered site such as the brain can take place, immune reactivity as a result of vaccination would be necessary to clear the neuroinvasive virus as well as virus in the periphery. - human fetal astrocytes, chemokines, HIV-1, MCP-1, dementia patients, CSF, MCP-1 promoter sequences